DE3801007C2 - Rapid traverse for a push cylinder, in particular for a push cylinder of a loading crane - Google Patents

Description

The invention relates to a rapid traverse circuit for a Thrust cylinder, in particular for a longitudinal thrust cylinder displacement of a boom section of the boom of a La dekranes, with one attached to the piston side of the thrust cylinder closed pressure line and one on the ring side of the Thrust cylinder connected return line, with a die Pressure line with pressure medium line connecting the return line, in one towards the piston side of the thrust cylinder opening check valve and one by pressurization Lock valve that can be unlocked via a control line.

In a known rapid traverse circuit according to DE 27 30 191 A1 the control line of the check valve is one of one Pump pressurized pressure line. The check valve is therefore unlocked and rapid traverse only possible when the pump is in Operation is set. A possible one turned on Rapid traverse for the cylinder then has the disadvantage that one the piston rod of the cylinder hanging load the piston can pull out the cylinder as long as the check valve is unlocked  is.

For a push cylinder for the longitudinal displacement of one or of several boom sections of a loading crane boom is the In the known rapid traverse gear, there is no security against pulling out with negative loads because of the not guaranteed with it Operational safety undesirable and even dangerous.

With a circuit described in DE 33 46 235 A1 rapid traverse is possible because there is a through channel is that with the pressure medium line in terms of function is comparable. In the through channel one sits against the effect a spring that closes a spring when the cylinder is pressed. A fuse with negative load is by the circuit the DE 33 46 235 A1 not reachable. A load wants the piston pull out of the cylinder, the spring holding the spring breaks Pressure together. The spring then opens the through channel again. The piston is then in a floating position, and the load can pull out the piston easily.

The 26 09 434 C2 shows a rapid traverse, with a Check valve. However, the check valve is not in one Fluid line connecting the pressure line and the return line. One always switched on in the known circuit Rapid traverse is only switched off by the check valve.

The US 35 24 386 specifies a circuit in the external Rapid traverse can be switched on with a valve. As long as the valve is in the open position, i.e. is open  rapid operation follows. Negative burdens can Pull the piston out easily and consequently it is a negative load safety device unavailable.

The invention has for its object a rapid traverse to provide the type mentioned at the beginning, which the rapid traverse automatically switches off, especially if negative, the The piston rod of the push cylinder pulls out loads on Thrust cylinders act.

According to the invention, this object has been achieved by that the control line of the check valve from the pressure line the thrust cylinder is branched and that the unlocking of the Check valve is adjustable to different control pressures.

This from the ring side of the push cylinder when the piston extends pressure medium pressed into the reflux line flows through the additionally attached pressure medium line and the two check valves to the pressure line if the unlockable Check valve with flow direction to the piston side of the Thrust cylinder is unlocked. The one from the ring side of the push cylinder displaced pressure medium flow becomes the pressure medium flow slammed in the pressure line, causing the amount of pressure medium flowing to the piston side of the cylinder per unit of time increased and the piston of the push cylinder one can perform faster extension movement. The push cylinder works with the check valve unlocked in each case Rapid traverse activated or deactivated after blocking position. This Rapid traverse is particularly advantageous in a loading crane  applicable when boom sections are extended without load should be to move the loading crane to a desired operating position to lift corresponding loads. Since that Unlockable check valve on by pressurization is operated check valve, the control line of the Pressure line of the thrust cylinder is branched, results the advantage that the rapid traverse of the thrust cylinder is automatic switches on as soon as pressure on the Piston side of the thrust cylinder is given. The rapid traverse works automatically. The pressure drops in the Control line from, e.g. B. because a negative load on the piston rod wants to pull out, the shut-off valve goes into the locked position and rapid traverse is automatically switched off. So is also given a negative load protection for the thrust cylinder.  

The rapid traverse scarf stands out after further training tion in that a be in the return line Actable 2-2 way valve is used. This 2-2 way seven til can advantageously be operated depending on the pressure, with a second control transmission to at least one cylinder space of a working cylinder another for pivoting the loading crane boom in a vertical level is connected. Furthermore, a bypass is device provided for the 2-2 way valve, in which a bypass Check valve with flow direction used to the push cylinder is. The combination of 2-2 way valve according to the invention second control line connected to a working cylinder and Um the non-return valve also automatically causes a load-dependent Switching between rapid traverse and normal thrust cylinder otherwise.

Loads hanging on a jib of a loading crane can be both positive as well as negatively on the corresponding working cylinders we ken. One on an articulated arm, which by means of an articulated cylinder is pivotable, held load, depending on the position of the Articulated arm on the piston of the articulated cylinder also one out exert a pulling load. A negative load then acts on the articulated cylinder. In the opposite case, where the load on the articulated cylinder or another working cylinder like this causes the piston to be pushed in by the load, acts a positive burden.

In the normal position, without loading the boom, or of the entire loading crane, the 2-2 way valve is in egg  ner locked position, so that when extending the push cylinder The rapid traverse circuit described above is activated. Has a po sitive and / or negative load on a cylinder in the second control line connected to the working cylinder generates a control pressure resulting from the load, which 2-2 directional valve brings into a open position. From the thrust Cylinder pressure medium pressed into the return line can be there by passing the open 2-2 way valve normally flow back without the rapid traverse switching being activated.

The 2-2 way valve is a known adjustable one Valve, so that advantageously the load pressure switching point of the 2-2 way valve is adjustable, independent depending on the respective pressure conditions in the with the Rapid shift circuit provided pressure medium circuit of the Schubzy linders.

The rapid traverse circuit according to the invention thus enables a rapid gear for the push cylinder on the boom of a loading crane, the switches off automatically as soon as a predetermined limit positive and / or negative loads exceeding the value.

The bypass check valve still has the special ren advantage that pressure pressed into the return line with tel must take the forced route through the pressure medium line to to generate the rapid traverse. Depends on one at the end load of a loading crane hanging the rapid traverse over the 2-2 Directional control valve switched off, the pressure medium can flow back Drain the line normally via the 2-2 way valve. The rapid traverse  is then not activated. The bypass check valve has also the task of refluxing the pressure medium in the Forced to return line via the 2-2 way valve. Conversely, even with the 2-2 way valve closed, the Bypass check valve pressure medium in the return line be pressed, for example, to push the push cylinder to on bring to bring.

As already described, the working cylinder that the Switchover from rapid traverse to normal thrust cylinder depending on a positive and / or negative load controls, one supported on the loading crane column, on the main arm of the loading crane boom attacking lifting cylinder. As well can, if the loading crane boom is designed as an articulated arm, the working cylinder be an articulated cylinder.

The crane is designed so that only positive loads the working cylinder can act, so the second control line be connected to the piston side of the working cylinder.

If only negative loads occur, the second tax liability device connected to the ring side of the working cylinder. Tre both negative and positive loads on the working cylinder that of a loading crane, the second control line is connected to the col ben and connected to the ring side of the working cylinder, in each of the branch lines to the ring side and to the piston each side a check valve with flow direction to 2-2 We valve is inserted.

The entire invention can be particularly advantageous  Rapid traverse switching can be carried out in a block design. In doing so, everyone Valves grouped in a block, creating the circuit can also be installed in the immediate vicinity of the push cylinder, with the advantage that low pressure losses occur. Everyone Loading crane is easy with the rapid traverse circuit according to the invention Can be retrofitted and due to the block construction there is hardly any additional Piping effort necessary.

An embodiment is shown in the drawing. It demonstrate:

Fig. 1 is a schematic side view of a loading crane with loading crane column and from the main arm and the outer boom best hendem boom,

Fig. 2 is a circuit diagram of the rapid-motion in a exporting tion for use with a truck mounted crane according to Fig. 1,

Fig. 3 shows the diagram of the rapid-motion according to Fig. 2, in an operative position for extending the Schubzylin DERS under load pressure

Fig. 4 shows the circuit diagram of the circuit of FIG. 3 in an operating position for extending without load pressure and

Fig. 5 shows the circuit diagram in an operating position for retracting the thrust cylinder without load pressure.

Fig. 1 shows the schematic side view of a loading crane of conventional design, the crane frame 1 with side supports from 2 and 3 on the chassis of a truck is not shown here can be built. On the crane frame stands a crane column 5 rotatable about the vertical axis 4 , at the upper end of which a main arm 7 is articulated at 6. The main arm 7 is part of the crane boom and can be pivoted in a vertical plane by means of the supported on the crane column 5 Ar working cylinder 8 . At the free end of the Hauptar mes 7 there is an articulated axis 9 , about which an articulated arm 10 is also pivotable in the vertical plane. The Schwenkbewe conditions of the articulated arm 10 are generated by an articulated cylinder 11 , which is supported on the main arm 7 and which acts via a He bell strap 12 on the articulated arm 10 .

The articulated arm consists of several telescopic boom sections 13 , 14 and 15 . At 16 , a push cylinder 17 is supported on the articulated arm 10 , the piston rod engages at 18 on the boom section 13 . In the piston rod ge a second piston rod 19 is guided, which acts on the boom section 14 at 20 . A third piston rod can also be provided, which is guided in the second piston rod 19 and with which the boom section 15 can be pushed out or drawn in.

The design of the articulated arm with thrust cylinder 17 and telescopically displaceable boom sections 13 , 14 and 15 is known and is not described further here.

In Fig. 2 is a circuit diagram of a rapid traverse with which the thrust cylinder 17 can either be pushed out at normal speed, which depends on the amount of pressure medium supplied by a pump 21 , or in a rapid traverse at an increased speed. A pressure line 24 is connected to the piston side 22 of the thrust cylinder 17 , in which the schematically indicated piston 23 with the piston rod 18 arranged thereon is guided. On the ring side 25 of the push cylinder 17 , a return line 26 is closed. With 27 a known actuating valve is designated with which the flow of the pressure medium generated by the pump 21 can be given to the pressure line 24 . The actuating valve also allows the flow to give the return line or, as Darge is here, the pressure line 24 and the return line 26 to close at the same time, which corresponds to a normal position or locking of the push cylinder 17 .

Pressure line 24 and return line 26 are connected to one another via a pressure medium line 28 , in which a return check valve 29 and an unlockable check valve sits, which is referred to here as check valve 30 . Check valve 29 and check valve 30 have opposite direction of flow, the check valve 30 having a flow direction to the piston side 22 of the push cylinder 17 . The blocking valve 30 is drawn in the blocking position in FIG. 2. The check valve 30 can be unlocked by pressurization, a Steuerlei device 31 is connected to the pressure line 24 .

In the return line there is a 2-2 way valve 32 which can also be actuated by pressurization. The second control line 33 of the 2-2 way valve leads to a working cylinder GE. The working cylinder can be either the lifting cylinder 8 or the articulated cylinder 11 ( FIG. 1).

There are three examples drawn side by side, which indicate how the second control line to the working cylinders 8 , 11 can be connected, the example shown on the left, for example, a connection with positive loads on the working cylinders 8 , 11 , the middle example for negative ones Loads on the working cylinders and the example on the right shows a connection with both negative and positive loads on the working cylinders 8 or 11 . In one application of Eil Fig. 2 transmission according to a loading crane, in which at ei the second control line nem 33 influencing working cylinder 8 or 11 both negative and positive loads can be added, the second control line 33 to both the piston side and the Ring side of the working cylinder 8 or 11 ruled out, with a Rückschlagven valve 36 and 37 respectively in each branch line 34 , 35 .

The 2-2 directional valve 32 inserted into the return line 26 is assigned a bypass line 38 in which a reverse check valve 39 is arranged with the flow direction to the thrust cylinder. The operation of the circuit according to FIG. 2 using a loading crane according to FIG. 1 will be described below with reference to FIGS. 3, 4 and 5.

FIG. 3 shows the circuit diagram in an operating position which enables the push cylinder to be extended under load by a load suspended from a jib of a loading crane. If the control pressure increasing in the control line 33 as a function of the load acting on the working cylinders 8 or 11 ( FIG. 1) is so great that the force of the spring 40 indicated on the 2-2 way valve 32 is overcome, this is 2- 2-way valve switched to free flow position. The actuating valve 27 is also switched to the free passage of the pressure line 24 or the return line 26 , so that via the Drucklei device 24 from the pump 21 ( FIG. 2) pressure medium flows to the piston side of the thrust cylinder 17 . The displaced from the ring side 25 by the extending piston 23 pressure medium flows freely via the return line 26 through the switched to passage te 2-2 way valve 32 via the actuating valve 27 . In the operating position shown in Fig. 3, the rapid traverse device is not activated.

The activated rapid traverse circuit shows the circuit diagram according to FIG. 4, in which the spring 40 has brought the 2-2-way valve 32 into the blocking position due to non-existent pressure in the control line 33 . From the pump 21 ( Fig. 2) in the pressure line 24 pressure medium flows to the Schubzylin and builds up on the piston side 22 pressure that causes the piston 23 to extend. The displaced on the ring side 25 of the Schubzy Linders 17 pressure medium can not flow back through the actuating valve 27 due to the blocking of the return line 26 through the 2-2 way valve located in the blocking position and that in the bypass line 38 located check valve 29 . It flows through the opening check valve 29 into the pressure medium line 28 . The check valve 30 is unlocked via the control line 31 as soon as a corresponding pressure is built up in the pressure line 24 to which the control line 31 is connected. From the ring side 25 of the Schubzylin 17 displaced pressure medium thus flows when the check valve 30 is unlocked via the pressure medium line 28 to the pressure line 24 , which increases the amount of pressure medium supplied to the piston side 22 of the thrust cylinder 17 . This has the effect that the piston 23 can extend at a correspondingly increased speed, that is to say in a rapid traverse.

Fig. 5 is a circuit diagram showing in an operating position, in which the piston 23 of the pushing cylinder is to retract 17th Be the actuating valve 27 is brought into a switching position in which the pressure medium pumped by the pump 21 ( FIG. 2) flows via the return line 26 to the ring side 25 of the push cylinder 17 , the bypass check valve 39 opening. The return flow of the pressure medium from the piston side 22 takes place di rectly via the actuating valve 27 to the pressure medium container not shown here. A flow of pressure medium from the ring side 25 to the piston side 22 via the pressure medium line 28 is just in case of positive or negative load if by the check valve 30 and the upstream check valve 29 prevented.

Claims (10)

1. Rapid traverse for a thrust cylinder, in particular for a thrust cylinder for the longitudinal displacement of a boom section of the boom of a loading crane, with a pressure line connected to the piston side of the thrust cylinder and a return line connected to the ring side of the push cylinder, with a pressure medium line connecting the pressure line with the return line which have a check valve opening towards the piston side of the thrust cylinder and a check valve which can be unlocked by pressurizing it via a control line,
characterized,
that the pressure line ( 31 ) of the check valve ( 30 ) is branched off from the pressure line ( 24 ) of the push cylinder ( 17 ) and that the unlocking of the check valve ( 30 ) can be set to different control pressures. 2. rapid traverse according to claim 1, characterized in that in the return line ( 26 ) an actuatable 2-2 way valve ( 32 ) is used. 3. rapid traverse according to claim 2 for use in a loading crane, characterized in that the 2-2 way valve ( 32 ) can be actuated in a pressure-dependent manner, a second control line ( 33 ) to at least one cylinder space of a working cylinder ( 8 ; 11 ) for pivoting the Loader boom is connected in a vertical plane. 4. rapid traverse according to claim 2 or 3, characterized in that a bypass line ( 38 ) for the 2-2 way valve ( 32 ) is provided, in which a bypass check valve ( 39 ) with flow direction to the thrust cylinder ( 17 ) is used. 5. rapid traverse according to claim 3, characterized in that the working cylinder is supported on a loading crane column ( 5 ), on a main arm ( 7 ) of the loading crane boom engaging lifting cylinder ( 8 ). 6. rapid traverse according to claim 3, characterized in that, when the loading crane boom is designed as an articulated arm, the working cylinder is an articulated cylinder ( 11 ). 7. rapid traverse according to claim 3 and one of Ansprü che 5 and 6, characterized in that the second control line ( 33 ) to the piston side of the working cylinder ( 8 ; 11 ) is connected. 8. rapid traverse according to claim 3 and one of Ansprü che 5 and 6, characterized in that the second control line ( 33 ) is connected to the ring side of the working cylinder ( 8 ; 11 ). 9. rapid traverse according to claim 3 or one of claims 5 or 6, characterized in that the second control line ( 33 ) is connected to the piston and to the ring side of the working cylinder ( 8 ; 11 ) and that in each branch line ( 34 , 35 ) a check valve ( 36 , 37 ) with flow direction to the 2-2 way valve ( 32 ) is used on the ring side and on the piston side. 10. rapid traverse according to one of claims 1-9, characterized characterized that it is carried out in block construction.